• Korean Institute of Interior Design Journal
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• v.27 no.3
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• pp.136-144
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• 2018

The purpose of this study is to examined the unconscious response of the pupil in the observation toward the image in the eye-tracking experiments that target on a large complex cultural space. Twenty-five men participated in this experiment and the observation data were analyzed in seconds per minute on watching time. It could examine the unconscious response of information searching in the change of pupil size in the process of observing the space. The results could be defined as following several points. First, it was possible to outline the unconscious response characteristics of pupil by analyzing sudden changes in pupil size as total, cumulative, and individual. The response characteristics using frequency and time can be utilized as the analytical method to examine the degree of interest of spatial components according to the purpose of analysis in the future. Second, according to the over ${\pm}5%$ of cumulative variation rate on the pupil size change, during in the 60 seconds, the continuous pupil dilation was used 25.2 seconds in 8.8 rounds and the pupil reduction was used 18.0 seconds in 7.0 rounds. Third, when the variation rate of ${\pm}5%$ or more was regarded as the sudden changes on pupil size by individual variation, the pupil dilation was 7.2 rounds of 8.6 seconds and pupil reduction was 6.0 seconds in 5.0 rounds. This means that the pupil increases 9.3% in one expansion and decreases -8.5% in the reduction process. As regarding pupil changes as cumulative rate, it appeared high change rate on pupil reduction but it became higher on pupil dilation in individual.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.82-89
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• 1998

PI controller has been used in the servo system. However the time response of the system designed using the PI control scheme does not provide with desirable time response in case of variation in system parameters or perturbation like a torque disturbance. LMFC(Linear model following controller) is being used to make the response of the system follow that of the model even though the parameter variation or the perturbation occurs. In this paper, a design method, RMFC(Robust Model Following Controller) is proposed, which use an auxiliary model in addition to the LMFC, which affords robustness against the low frequency load torque disturbance. The proposed method is more useful to rejecting the low frequency torque disturbance than LMFC. Proposed method is verified by simulation and experiment.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.26-35
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• 2004

As part of thrust control technology research on turbopump-fed type liquid-propellant rocket engine system, the low frequency dynamic characteristics of turbopump was investigated. It can be described that a turbopump system has a 1st-order lag element. When the value, which was resulted by subtraction of the variation of turbine moment with respect to the variation of revolution number from the variation of pump moment with respect to the variation of revolution number, was positive, the time constant of the 1st-order lag element was positive which stood for a stable system. Increasing the above-mentioned valve within positive range leaded to the increase of response and to the decrease of controllability.

• Coupled systems mechanics
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• v.7 no.3
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• pp.353-371
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• 2018

The Wavenumber or more accurately Wavenumber-FD approach was initially introduced for two-dimensional dynamic analysis of concrete gravity dam-reservoir systems. The technique was formulated in the context of pure finite element programming in frequency domain. Later on, a variation of the method was proposed which was referred to as Wavenumber-TD approach suitable for time domain type of analysis. Recently, it is also shown that Wavenumber-FD approach may be applied for three-dimensional dynamic analysis of concrete arch dam-reservoir systems. In the present study, application of its variation (i.e., Wavenumber-TD approach) is investigated for three-dimensional problems. The method is initially described. Subsequently, the response of idealized Morrow Point arch dam-reservoir system is obtained by this method and its special cases (i.e., two other well-known absorbing conditions) for time harmonic excitation in stream direction. All results for various considered cases are compared against the exact response for models with different values of normalized reservoir length and reservoir base/sidewalls absorptive conditions.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.47-58
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• 2005

Dynamic response analysis in time dimain is conducted for floating bridges with discrete pontoons subject to spatial variation of ground motions. The Spatial variation of ground motions is considered with the coherency function model which represents wave passage, incoherence and local site effects. The superstructure of the bridge is represented by space frame and elastic catenary cable elements, the abutment us modelde with the spring element of FHWA guideline for considering soil structure interaction and the concept of retardation function is utilized to consider the frequency dependency of the hydrodynamic coefficients which are obtainde by boundary element method. multiple support excitations considering the spatial variation. The noticeable amplification of the response can be shown when the spatial variation of ground motions is incorporated in the anallysis of floating bridges.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.2
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• pp.239-246
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• 2006

This paper describes the scheme of sliding mode control (SMC) to adopt the conventional slip frequency vector drives. The purpose of sliding mode control is to achieve an accurate, robustness of response for ac servomotor speed control. A sliding mode control design method is proposed for a speed control of an induction servomotor. The control law is composed of the variable structure component and the suppressed coefficients to suppress load disturbance and variation of external parameters. The proposed control scheme is simulated by the computer which is installed in an ideal ac servomotor. The simulation results show that the proposed design method has robustness and accuracy in the speed response by adjusting the suppressed coefficients for load disturbance and the motor mechanical parameter variation.

• Geomechanics and Engineering
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• v.5 no.3
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• pp.223-240
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• 2013

In the present study an attempt was made to predict the complex nonlinear parameters of the soil-pile system subjected to the vertical vibration of rotating machines. A three dimensional (3D) finite element (FE) model was developed to predict the nonlinear dynamic response of full-scale pile foundation in a layered soil medium using ABAQUS/CAE. The frequency amplitude responses for different eccentric moments obtained from the FE analysis were compared with the vertical vibration test results of the full-scale single pile. It was found that the predicted resonant frequency and amplitude of pile obtained from 3D FE analysis were within a reasonable range of the vertical vibration test results. The variation of the soil-pile separation lengths were determined using FE analysis for different eccentric moments. The Novak's continuum approach was also used to predict the nonlinear behaviour of soil-pile system. The continuum approach was found to be useful for the prediction of the nonlinear frequency-amplitude response of full-scale pile after introducing the proper boundary zone parameters and soil-pile separation lengths.

• Journal of KSNVE
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• v.9 no.1
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• pp.163-173
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• 1999

Precise and reasonable modelling is necessary and indispensable to the analysis of dynamic characteristics of mechanical structures. Also. the effective prediction of the change of modal properties due to the variation of design parameters is required especially for the application of finite element method to the structural dynamics problems. To meet those necessity and requirement, three model updating algorithms are proposed for finite element methods. Those algorithms are based on sensitivity analysis of the modal data obtained from experimental modal analysis(EMA) and analytical modal analysis(AMA). The adapted sensitivity analysis methods of the algorithms are 1)eigensensitivity(EGNS) method. 2)frequency response function sensitivity(FRFS) method. 3)sensitivity based element-by-element method (SBEEM), Singular value decomposition(SVD) is used for performing eigenanalysis and parameter estimation in the updating process. Those algorithms are applied to finite element of a plate and the updating capability of each algorithm is compared in terms of accuracy. reliability and stability of the updating process. It is shown that the model updating method using frequency response function is superior to the other methods in view of various updating capabilities.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.5
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• pp.491-499
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• 1999

This study was designed to evaluate the efficacy of dynamic parameters, such as correlation dimension $D_2,$ by comparing spectral electroencephalographic (EEG) parameters. These parameters are used to estimate the depth of halothane anesthesia as defined by the presence of body movement in response to a tail clamp. Six rats were used and each of them was exposed to halothane sequentially at the concentrations of 0%, 0.5%, 1.0% and 1.5% for 30 min. A tail clamp was applied every five min and the movements were recorded at each concentration level. The spectral parameters and the dynamic parameters were derived from 20-sec and 10-sec segments, respectively, from the last 5-mins of EEG recording at each concentration level. Correlation coefficients between the parameters and the movements were calculated. Standardized values of three parameters, betaL power, median power frequency (MPF), and $D_2$ were derived by calculation based on the number of animals showing the movement in response to a tail clamp. The betaL power had the largest correlation coefficient to spontaneous movement and to the response to a tail clamp than any other band parameter. MPF had a better correlation with the movement than 90% spectral edge frequency. Among the dynamic parameters, $D_2$ on the parietal cortex had a better correlation with the movement. The level of deviation and variation of standardized $D_2,$ MPF, and betaL were significant (p<0.01). The order of deviation and variation was; betaL power > MPF > $D_2.$ The correlation dimension serves as a better index for the depth of halothane anesthesia defined in forms of a response to external stimulation.

• Structural Engineering and Mechanics
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• v.88 no.2
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• pp.109-115
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• 2023

In this paper, frequencies of zigzag structure of carbon nanotubes isinvestigated based on Donnell shell theory. These tubes are wrapped with the ring supports in the axial direction. The fundamental frequency curves displayed in article show the dependence of vibrations attributes to zigzag single walled carbon nanotubes. Various zigzag indices are introduced against the variation of length to predict the vibration. Also, the influence of ring supports is sketched with proposed structure for frequency analysis. The frequencies of zigzag tube decreases as the length increases. It is observed that the frequencies decreases with ring support and have higher frequencies without ring. The problem is formulated using Partial Differential Equation. Three expressions of modal deformation displacement functions is used for the elimination of temporal variation to form the solution in the eigen from. For the stability of present study the results are compared with experimentally and numerically in the open text.